Previous case reports and non randomized studies have indicated that inhalation of aerosolized alprostadil may offer a new life saving strategy in intractable pulmonary hypertension and ARDS. Further, advantages of inhaled iloprost include the lack of adverse reactions and toxic side effects as well as convenient and more cost-effective administration. Due to the irreversible nature of ARDS associated with high rate of mortality also affecting resource allocation in critically ill patients, we suggest carrying out this study in our intensive care unit (ICU), where the incidence is > 10% resulting in almost 90% mortality (ICU Quality Indicators Jan-Apr 20048).